1. Field of the Invention
This invention relates to a dialysis machine with safety monitoring and a corresponding method for monitoring safety.
2. Description of the Related Art
As is known, dialysis machines incorporate a dialysis unit which is connected to a patient by means of an extracorporeal circulation line and which is controlled by means of specific actuators by a control system which ensures that the most appropriate dialysis conditions for the treatment required are maintained at all times on the basis of the operator's settings and adjustments.
In order to ensure that the dialysis unit always operates correctly, a monitoring system is generally provided to check consistency between the set conditions and the actual conditions, to reveal any situations which are potentially hazardous to the patient and to generate corresponding commands for returning the machine to a non-hazardous situation. In a known dialysis machine both the control and monitoring functions are performed by a single processor. This arrangement is however disadvantageous in that it does not ensure a sufficient level of safety if there should be a fault in the processor, one of the sensors or one of the actuators. In order to overcome this problem and increase the safety of the machine, separate control and safety systems each provided with their own sensors and their own actuators, are provided in another known dialysis machine. This arrangement, according to which in practice all detection and actuation members are duplicated, in fact provides a sufficient level of safety, but at the cost of considerably greater structural complexity, which has a repercussion on the cost of the machine itself.
The object of this invention is therefore to provide a dialysis machine which overcomes the disadvantages of known machines, and in particular provides optimum safety in respect of possible faults, with a low system cost.